Mask



FIG. 1 is a perspective view of a mask showing my new design;

FIG. 2 is a side elevation as seen from the right side of FIG. 1;

FIG. 3 is a side elevation as seen from the left side of FIG. 1;

FIG. 4 is a front elevation thereof;

FIG. 5 is a rear elevation thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a mask, as shown and described. 